The manufacture of apparel has changed from a wholly hand manipulated, machine sewing operation to a series of work stations where parts of the garment are made in a more-or-less semiautomated manner. These parts are then assembled in a hand manipulated, machine sewing operation. This change has reduced the labor content of apparel, such as shirts, so that much of the manufacturing operation has returned to the better developed countries from underdeveloped countries where labor costs are quite low.
Three of the processes which have been semiautomated are the manufacture of shirt cuffs, pocket flaps and shirt collars from cut blanks of material into a subassembly which is ready to be sewn onto panels of fabric which will ultimately become a shirt. There are three distinct operations: (1) a running operation in which fabric blanks are sewn together along a path near three sides, (2) an inverting and pressing operation in which the workpiece is turned inside out and ironed and (3) a top stitching operation in which a second series of stitches are sewn near the same three sides of the blanks.
Cuff, collar and pocket flap running and top stitching machines have become quite similar because the operations are quite similar. Exemplary state of the art cuff and collar machines offered by applicant's assignee are found in U.S. Pat. No. 4,841,887 and U.S. patent application Ser. No. 08/131,603, filed Oct. 5, 1993 and entitled SEMI-AUTOMATIC SEWING STATION, now U.S. Pat. No. 5,421,278, the disclosures of which are incorporated herein by reference. These machines comprise a smooth horizontal table, a work holder where a textile workpiece is positioned by a worker and manipulated by the holder, a sewing machine, a transfer arm that moves to the work holder, pushes the workpiece against the table, slides the workpiece to the sewing machine and then moves the workpiece around under the sewing needle as stitching occurs and a digital controller for energizing all of the components of the device at the correct times. It is this type device that this invention most nearly relates.
One common semi-automated operation is called running. A fabric workpiece is first prepared by juxtaposing a front, a back and a backing. A generally U-shaped seam is sewn in a running operation to leave a central pocket and one unstitched edge. The shape of the workpiece, the seam and the pocket depend on whether the workpiece is going to be a cuff, a pocket flap or a collar and on the particular design desired in the end product. The fabric workpiece is trimmed, turned inside-out and pressed in one operation and top stitched in a second separate operation. The workpiece is trimmed at the corner because, when it is inverted, there is normally too much material in the corner causing the finished workpiece to appeared puckered. Special purpose machines are used to trim, invert and press cuff, pocket flap and collar workpieces such as Model DS515D from Bou-Yue Manufacturing Co., Ltd. of Taiwan.
Top stitching is very similar to running because the stitching is along generally the same path. In a top stitching operation, the textile workpiece is taken from the inverter/presser, placed in a guide and smoothed down by the worker and the transfer arm moves the workpiece from the guide to the sewing station.